OptParse is a module introduced in Python2.3 that makes it easy to write command line tools.
You give a description of the options that the program can receive, and OptParse will do reasonable stuff for you.
For example:
1 import optparse
2
3 if __name__=="__main__":
4 parser = optparse.OptionParser()
5 parser.add_option( "-H", "--host", dest="hostname", default="127.0.0.1",
6 type="string", help = "specify hostname to run on" )
7 parser.add_option( "-p", "--port", dest="portnum", default=80,
8 type="int", help = "port number to run on" )
9
10 (options, args) = parser.parse_args()
11 hostname = options.hostname
12 portnum = options.portnum
[http://www.python.org/doc/current/lib/module-optparse.html Official Python 2.3 OptParse Documentation]